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Felicity Cutts

Publications and source records attributed to Felicity Cutts.

12 recordsLinked to original sources
PubMed2006

Chapter 15: HPV vaccine use in the developing world.

Human papillomavirus (HPV)-related morbidity and mortality from cervical cancer primarily occurs in the developing world, where, unfortunately, access to vaccines in general, and expensive newer vaccines in particular, is often more limited than in the industrialized world. In addition, secondary prevention methods such as HPV screening, Pap testing, or visual inspection are uncommon in the developing world. The HPV vaccine will be first introduced into the industrialized countries and it will then, over the course of time, become used in the developing countries. HPV vaccine should be introduced in the framework of comprehensive cervical cancer control, and offers an opportunity to bring together a wide range of constituents who have not to date worked closely on vaccination. Ultimately, the decision of whether and when a vaccine will be introduced will depend on individual countries. To prepare for decisions on HPV vaccine use, the sexual and reproductive health (SRH; including adolescent health), immunization, and cancer control communities need to work together to analyze the appropriate data and build international and national consensus. The timeframe for other newer vaccines, such as hepatitis B and Hib, has been measured in decades, and the challenge to the public sector is to greatly shorten the time needed to make HPV vaccines available and affordable for the developing world, where their impact will be greatest.

Developing Countries↗
PubMed2006

HIV-1 infection as a risk factor for incomplete childhood immunization in Zambia.

Immunizations are of particular importance for human immunodeficiency virus type 1(HIV-1)-infected children as they are at increased risk of severe disease and death from several vaccine-preventable diseases. Outside the United States, however, research on the impact of the HIV-1 epidemic on childhood immunization coverage is sparse. We conducted a nested case-control study in hospitalized children with measles to assess whether HIV-1 infection was a risk factor for incomplete immunization with diphtheria-tetanus-pertussis vaccine (DTP) and oral polio vaccine (OPV). Of 473 children, whose immunization status was determined from the immunization record or maternal recall, 23% were incompletely immunized and 19% were HIV-1 infected. After adjusting for age, sex, and measles vaccination status, HIV-1 infection was significantly associated with incomplete immunization with DTP and OPV (adjusted OR 1.9; 95% CI 1.1, 3.3). In a subset of children for whom information on maternal education was available, less than 7 years of school education was a risk factor for incomplete immunization (adjusted OR 3.7; 95% CI 1.8. 7.5). Children from homes with more than three children were twice as likely to be incompletely immunized as those from homes with one to three children. Our findings suggest that HIV-1-infected children are at increased risk of vaccine-preventable diseases not only because of impaired immune responses but because of lower rates of vaccine coverage.

Child, Preschool↗
PubMed2005

Evaluating the impact of the HIV pandemic on measles control and elimination.

OBJECTIVE: To estimate the impact of the HIV pandemic on vaccine-acquired population immunity to measles virus because high levels of population immunity are required to eliminate transmission of measles virus in large geographical areas, and HIV infection can reduce the efficacy of measles vaccination. METHODS: A literature review was conducted to estimate key parameters relating to the potential impact of HIV infection on the epidemiology of measles in sub-Saharan Africa; parameters included the prevalence of HIV, child mortality, perinatal HIV transmission rates and protective immune responses to measles vaccination. These parameter estimates were incorporated into a simple model, applicable to regions that have a high prevalence of HIV, to estimate the potential impact of HIV infection on population immunity against measles. FINDINGS: The model suggests that the HIV pandemic should not introduce an insurmountable barrier to measles control and elimination, in part because higher rates of primary and secondary vaccine failure among HIV-infected children are counteracted by their high mortality rate. The HIV pandemic could result in a 2-3% increase in the proportion of the birth cohort susceptible to measles, and more frequent supplemental immunization activities (SIAs) may be necessary to control or eliminate measles. In the model the optimal interval between SIAs was most influenced by the coverage rate for routine measles vaccination. The absence of a second opportunity for vaccination resulted in the greatest increase in the number of susceptible children. CONCLUSION: These results help explain the initial success of measles elimination efforts in southern Africa, where measles control has been achieved in a setting of high HIV prevalence.

Adolescent↗
PubMed2005

Neonatal measles immunity in rural Kenya: the influence of HIV and placental malaria infections on placental transfer of antibodies and levels of antibody in maternal and cord serum samples.

INTRODUCTION: Young infants are protected from measles infection by maternal measles antibodies. The level of these antibodies at birth depends on the level of antibodies in the mother and the extent of placental transfer. We investigated predictors of levels of measles antibodies in newborns in rural Kenya. METHODS: A total of 747 paired maternal-cord serum samples (91 from human immunodeficiency virus [HIV]-infected and 656 from HIV-uninfected mothers) were tested for measles immunoglobulin G antibodies. Placental malaria infection was determined by biopsy. Data on pregnancy history, gestational age, and anthropometric and socioeconomic status were collected. RESULTS: Infants born to HIV-infected mothers were more likely (odds ratio, 4.6 [95% confidence interval {CI}, 2.2-9.7]) to be seronegative and had 35.1% (95% CI, 9.8%-53.2%) lower levels of measles antibodies than did those born to HIV-uninfected mothers. Preterm delivery, early maternal age, and ethnic group were also associated with reduced levels of measles antibodies. There was little evidence that placental malaria infection was associated with levels of measles antibodies in newborns. CONCLUSION: Our results suggest that maternal HIV infection may reduce levels of measles antibodies in newborns. Low levels of measles antibodies at birth render children susceptible to measles infection at an early age. This is of concern in sub-Saharan African countries, where not only is the prevalence of HIV high, but measles is the cause of much morbidity and mortality.

Adolescent↗
PubMed2004

Cost of delivering child immunization services in urban Bangladesh: a study based on facility-level surveys.

This facility-based study estimated the costs of providing child immunization services in Dhaka, Bangladesh, from the perspective of healthcare providers. About a quarter of all immunization (EPI) delivery sites in Dhaka city were surveyed during 1999. The EPI services in urban Dhaka are delivered through a partnership of the Government of Bangladesh (GoB) and non-governmental organizations (NGOs). About 77% of the EPI delivery sites in Dhaka were under the management of NGOs, and 62% of all vaccinations were provided through these sites. The outreach facilities (both GoB and NGO) provided immunization services at a much lower cost than the permanent static facilities. The average cost per measles-vaccinated child (MVC), an indirect measure of number of children fully immunized (FIC-the number of children immunized by first year of life), was 11.61 U.S. dollars. If all the immunization doses delivered by the facilities were administered to children who were supposed to be immunized (FVC), the cost per child would have been 6.91 U.S. dollars. The wide gap between the cost per MVC and the cost per FVC implies that the cost of immunizing children can be reduced significantly through better targeting of children. The incremental cost of adding new services or interventions with current EPI was quite low, not significantly higher than the actual cost of new vaccines or drugs to be added. NGOs in Dhaka mobilized about 15,000 U.S. dollars from the local community to support the immunization activities. Involving local community with EPI activities not only will improve the sustainability of the programme but will also increase the immunization coverage.

Bangladesh↗
PubMed2003

Efficacy of polysaccharide pneumococcal vaccine in adults in more developed countries: the state of the evidence.

We review studies on the efficacy against disease caused by Streptococcus pneumoniae of the 23-valent polysaccharide pneumococcal vaccine in adult populations in the more developed countries. Meta-analyses of primary vaccine trials have attempted to reduce uncertainty from lack of power. Vaccine efficacy calculated from studies in South African gold-miners and in Papua New Guinea, with high attack rates and differing serotype patterns, cannot automatically be applied to more developed countries. Meta-analyses will overestimate a protective effect if this clinical heterogeneity is ignored. Meta-analyses limited to trials in the more developed setting show no protective effect against pneumococcal pneumonia and a non-significant protective effect against bacteraemia. Lack of a specific diagnosis limits the ability to detect a protective effect against pneumococcal pneumonia. Most, but not all, observational studies confirm a protective effect against bacteraemia. An effect on mortality in more developed countries has yet to be documented.

Adult↗
PubMed2003

Incidence and risk factors of paediatric rotavirus diarrhoea in northern Ghana.

We measured the type-specific incidence of paediatric rotavirus diarrhoea in an area of northern Ghana. Over 1 year, diarrhoea 1717 episodes were identified, of which 677 (39%) were positive for rotavirus. Risk factors for rotavirus infection included old age, wasting, high Vesikari score and the episode occurring in the dry season. Rotavirus-positive episodes tended to be more acute, causing vomiting and greater dehydration, and were more likely to require hospitalization. The incidence was 0.089 episodes per person-year for all diarrhoea, and 0.035 for rotavirus diarrhoea. The observed incidence decreased markedly with distance from the nearest health centre, suggesting a large unobserved burden. G2P[6], G3P[4] and G9P[8] made up more than half the genotypes detected, but the remainder were diverse. There is a large burden of rotavirus diarrhoea, but the effectiveness of future vaccines could be diluted by the high polymorphism of the virus, and the difficulty of reaching remote populations.

Child, Preschool↗
PubMed2003

Effects of misclassification of causes of death on the power of a trial to assess the efficacy of a pneumococcal conjugate vaccine in The Gambia.

BACKGROUND: A reduction in cause-specific mortality may be the most important public health measure of the efficacy of a new vaccine. However, in developing countries, assignment of causes of deaths occurring outside hospitals can be assessed often only through the questioning of relatives about the signs and symptoms leading to death ('post-mortem questionnaire'). Causes assigned in this way have poor sensitivity and specificity. We illustrate the effects of this misclassification on the power of a large trial of a pneumococcal polysaccharide/protein conjugate vaccine with a mortality endpoint. METHODS: Required sample sizes to achieve a study with specified power were calculated for all-cause and acute lower respiratory tract infection (ALRI) mortality for different levels of sensitivity and specificity of post-mortem questionnaires. Data from active community-based surveillance and post-mortem questionnaires collected 1989-1993 from the study area were used in the calculations. FINDINGS: The mortality rate among children aged 6-29 months from all causes was 34.2 per 1000 child-years; 19% of deaths were attributable to ALRI. Assuming that pneumococci would be responsible for 50% of ALRI deaths and that the vaccine would cover 70% of disease serotypes and would be 90% effective against these serotypes, the expected efficacy of the vaccine would be 6.0% (19% x 50% x 70% x 90%) against all causes combined and 31.5% (50% x 70% x 90%) against deaths from ALRI. If, as suggested by various reports, the sensitivity and specificity of assigning a death to ALRI by post-mortem questionnaire are about 40% and 90% respectively, then the observed vaccine efficacy against ALRI (as classified using the post-mortem questionnaire) would fall to 20%, and the power to detect this would be reduced by approximately 40%. Furthermore, low sensitivity of diagnosis would lead to a falsely low estimate of the burden of ALRI mortality in the population and the trial might have greater power to detect a reduction in mortality from all causes combined than that estimated at the outset. CONCLUSIONS: Low sensitivity and specificity of diagnosis by post-mortem questionnaire may mean that the power of a trial to detect a reduction in all-cause mortality is similar to that to detect a reduction in ALRI mortality. Since the latter is more susceptible to bias from misclassification of cause of death, all-cause mortality may be the most suitable endpoint. Similar considerations apply to trials of interventions against other diseases for which a cause-specific endpoint is subject to substantial misclassification.

Africa↗
PubMed2003

Changing patterns of rotavirus genotypes in ghana: emergence of human rotavirus G9 as a major cause of diarrhea in children.

Genotyping of human rotaviruses was performed on 312 rotavirus-positive samples collected from 2,205 young children with diarrhea in the Upper East District of Ghana, a rural community. Of the 271 (86.9%) rotavirus strains that could be VP7 (G) or VP4 (P) characterized, 73 (26.9%) were of G9 specificity. The predominant G9 genotype was G9P[8], which constituted 79.5% of all G9 strains detected, followed by G9P[6] (12.3%), G9P[10] (2.7%), and G9P[4] (1.3%). G9 strains with mixed P types constituted 2.7% of all G9 strains found in the study. All the G9P[8] strains had a long RNA electrophoretic pattern with VP6 subgroup II specificity. Four G9 isolates, GH1319, GH1416, GH3550, and GH3574, which were selected based on the abundance of stool material and were representative of the three electropherotypes observed, were cloned and sequenced. The Ghanaian isolates shared more than 98% sequence nucleotide homology with other G9 strains from the United States (US1205), Malawi (MW69), Brazil (R160), Japan (95H115), and Nigeria (Bulumkutu). However, they showed only 95% nucleotide homology with the Thai G9 strain Mc345. Phylogenetic analysis of the nucleic acid sequence revealed the existence of at least three clusters, with Ghanaian strains forming one cluster, Nigerian and Brazilian strains forming a second cluster, and U.S., Malawian, and Japanese strains forming a third.

Antigens, Viral↗
PubMed2002

Prospective study of measles in hospitalized, human immunodeficiency virus (HIV)-infected and HIV-uninfected children in Zambia.

Measles in persons coinfected with human immunodeficiency virus (HIV) has been reported to be unusual in its presentation and frequently fatal. To determine the effect of HIV coinfection on the clinical features and outcome of measles, a prospective study of hospitalized children with measles was conducted between January 1998 and October 2000 in Lusaka, Zambia. One-sixth (17%) of 546 children hospitalized with laboratory-confirmed measles were coinfected with HIV. One-third of the HIV-infected children hospitalized with confirmed measles were <9 months old, compared with 23% of HIV-uninfected children (P=.03). Few differences in clinical manifestations, complications, or mortality were found between HIV-infected and HIV-uninfected children with measles. HIV-infected children constitute a significant proportion of children hospitalized with measles in countries with high HIV prevalence and are more likely to be younger than the age for routine measles immunization.

AIDS-Related Opportunistic Infections↗
PubMed2002

Suppression of human immunodeficiency virus replication during acute measles.

To determine the effect of measles virus coinfection on plasma human immunodeficiency virus (HIV) RNA levels, a prospective study of hospitalized children with measles was conducted between January 1998 and October 2000 in Lusaka, Zambia. Plasma HIV RNA levels were measured during acute measles and 1 month after hospital discharge. The median plasma HIV RNA level in 33 children with measles who were followed longitudinally was 5339 copies/mL at study entry, 60,121 copies/mL at hospital discharge, and 387,148 copies/mL at 1-month follow-up. The median plasma HIV RNA level in children without acute illness was 228,454 copies/mL. Plasma levels of immune activation markers were elevated during the period of reduced plasma HIV RNA. Plasma levels of several potential HIV suppressive factors also were elevated during acute measles. HIV replication is transiently suppressed during acute measles at a time of intense immune activation.

Acute Disease↗